Different types of acoustic devices have been used through the years. One type of device is a microphone. In a microelectromechanical system (MEMS) microphone, a MEMS die includes at least one diagram and at least one back plate. The MEMS die is supported by a substrate and enclosed by a housing (e.g., a cup or cover with walls). A port may extend through the substrate (for a bottom port device) or through the top of the housing (for a top port device). In any case, sound energy traverses through the port, moves the diaphragm and creates a changing potential of the back plate, which creates an electrical signal. Microphones are deployed in various types of devices such as personal computers or cellular phones.
Microphone performance variation can occur due to wide process ranges or sensitivity to process parameters. Additionally, variations in operating environment can translate into different microphone performance requirements depending upon the amplitude and the frequency of the sound present. In previous approaches, there is little done to shape the response of the microphone and thereby address these situations.
The problems of previous approaches have resulted in some user dissatisfaction with these previous approaches.